plugins_guidelines.md

Third Party Plugin Guidelines

Bevy has a plug and play architecture, where you can easily add plugins for new features, or replace built-in plugins with your own.

This document targets plugin authors.

Checklist

• Pick a reasonable, descriptive name
• Bevy/plugin version support table
• Turn off default Bevy features
• Choose a Bevy git/main tracking badge
• Pick a license
• Remove unnecessary or redundant dependencies
• Add cargo tests and CI
• Documentation and examples
• Publish your plugin
• Promote your plugin

Naming

You are free to use a bevy_xxx name for your plugin, but please be reasonable. If you are about to claim a generic name like bevy_animation, bevy_color, or bevy_editor, please ask first. The rationale is explained here.

Promotion

You can promote your plugin in Bevy's communities:

• Add it to Awesome Bevy.
• Announce it on Discord, in the #showcase channel.
• Announce it on Reddit.

Bevy Version Supported

Indicating which version of your plugin works with which version of Bevy can be helpful for your users. Some of your users may be using an older version of Bevy for any number of reasons. You can help them find which version of your plugin they should use. This can be shown as a simple table in your readme with each version of Bevy and the corresponding compatible version of your plugin.

bevy	bevy_awesome_plugin
0.4	0.3
0.3	0.1

Bevy Features

You should disable Bevy features that you don't use. This is because with Cargo, features are additive. Features that are enabled for Bevy in your plugin can't be disabled by someone using your plugin. You can find the list of features here.

bevy = { version = "0.4", default-features = false, features = ["..."] }

Main Branch Tracking

If you intend to track Bevy's main branch, you can specify the latest commit you support in your Cargo.toml file:

bevy = { version = "0.4", git = "https://github.com/bevyengine/bevy", rev="509b138e8fa3ea250393de40c33cc857c72134d3", default-features = false }

You can specify the dependency both as a version and with git, the version will be used if using the dependency from crates.io, the git dependency will be used otherwise.

Bevy is evolving very fast. You can use one of these badges to communicate to your users how closely you intend to track Bevy's main branch.

badge	description	code
	I intend to track main as much as I can	[](https://github.com/bevyengine/bevy/blob/main/docs/plugins_guidelines.md#main-branch-tracking)
	I will only follow released Bevy versions	[](https://github.com/bevyengine/bevy/blob/main/docs/plugins_guidelines.md#main-branch-tracking)

General Advices for a Rust Crate

This advice is valid for any Rust crate.

Licensing

Bevy is dual licensed under MIT or Apache 2.0, at your option. Most other Rust projects (including Rust itself) also use this dual-license approach. MIT-only is very popular and you might be tempted to just use that (Bevy also used to be MIT-only), but there are very good reasons to include both and we highly recommend using the dual MIT / Apache-2.0 license for your Bevy Plugins and crates:

• Including the Apache 2.0 license option significantly reduces the difficulty and boilerplate of proper license compliance in published games because you only need to include one copy of the Apache 2.0 license.
• Provides maximum compatibility with Bevy and Rust, making it easier to upstream your changes.

Small Crate Size

To avoid long build times in your crate and in projects using your plugin, you should aim for a small crate size:

• Disable Bevy features that you don't use
• Avoid large dependencies
• Put optional functionality and dependencies behind a feature

Documentation and Examples

Documentation and examples are very useful for a crate.

In the case of a plugin for Bevy, a few screenshots or movies/animated GIFs from your examples can really help understanding what your plugin can do.

Additionally, it can be helpful to list:

• Stages added by the plugin
• Systems used
• New components available

Tests and CI

Tests are always good! For CI, you can check this example for a quickstart using GitHub Actions. As Bevy has additional Linux dependencies, you should install them before building your project, here is how Bevy is doing it. Even if you don't have many (or any) tests, setting up CI will compile check your plugin and ensure a basic level of quality.

Publishing your Plugin

There are some extra fields that you can add to your Cargo.toml manifest, in the [package] section:

field	description
description	a description of the plugin
repository	URL of the plugin source repository
license	the plugin license
keywords	keywords for the plugin - "bevy" at least is a good idea here
categories	categories of the plugin - see the full list on crates.io
exclude	files to exclude from the released package - excluding the assets folder that you may have is a good idea, as well as any large file that are not needed by the plugin

Once a crate is published to crates.io, there are two badges that you can add to your README.md for easy links:

badge	code
	[](https://crates.io/crates/bevy_awesome_plugin)
	[](https://docs.rs/bevy_awesome_plugin)